1. Field of the Invention
This invention relates generally to resectoscope electrodes, and more particularly, to a resectoscope electrode assembly that simultaneously cuts and coagulates.
2. Description of Related Art
BPH is a benign overgrowth of the prostate gland that is situated at the bladder outlet. BPH is one of the most common conditions affecting men over the age of 50. The incidence increases with age and reaches 80 to 90% at 80 years. In the majority of patients, the BPH causes no symptoms. However, in a certain percentage of patients, the BPH will slowly and progressively obstruct the urinary outflow causing voiding symptoms of bladder obstruction and irritation. Furthermore and yet in a smaller percentage, these symptoms progress to cause complete urinary retention, urinary infections, bladder stones, and kidney damage. The decision to treat or not to treat patients is governed by the presence and absence of symptoms and their severity. Therefore, in the far majority of BPH patients (approximately 70%) who remain asymptomatic, no treatment is needed. In the symptomatic BPH patients, a wide variety of treatment strategies are available.
There are two groups of surgical therapies for BPH based according to the anesthesia requirement. The first group requires general or spinal anesthesia and includes open prostatectomy, transurethral resection of the prostate (TURP), transurethral incision oft he prostate (TUIP), transurethral vaporization of the prostate (TVP), visual laser assisted prostatectomy (V-LAP), contact laser prostatectomy, prostate balloon dilation, and intra-prostatic stents. TURP is the "gold standard" treatment. It has been the most efficacious and durable of all the surgical treatments, with a success rate of 80-90%.
The prostate is a highly vascular organ which bleeds during resection (TURP). Bleeding causes a decrease in visual clarity which in turn leads to a variety of intraoperative difficulties with undesirable consequences. The bleeding is the main offending factor responsible for the majority of the problems. FIG. 1 is a flow chart listing the complications of the standard TURP.
A typical resectoscope for transurethral resection consists of four main elements. The first element is a rigid telescope for observing the interior of the urinary tract where the surgical procedure is performed. The telescope comprises an objective lens and a series of relay lenses housed within an endoscope barrel or stem, the stem being connected to an eyepiece housing containing suitable lenses for proper magnification. The second element takes the form of a handle assembly commonly referred to as a working element. The working element can serve as the means for connecting electrosurgical current from an electrosurgical generator to the third element, an electrode assembly. The working element is also capable of slidably the electrode assembly along the longitudinal axis of the resectoscope. The combination of the telescope, working element, and electrode assembly is locked into a fourth element, a resectoscope sheath. The sheath consists of a tube and a union body and lock assembly. In the operative procedure the entire resectoscope is placed into the urethra.
The usual resectoscope electrode assembly is in the form of a U-shaped tungsten wire loop, the ends go to one or more wires that fit in a socket in a working element of the resectoscope for current conduction. The wire arms usually merge at their proximal ends and are jointed to an electrode lead extending back to the working element of the instrument. To brace the cutting loop so that it remains uniformly spaced from the telescope stem, a metal spacing sleeve is commonly provided between the telescope stem and either parallel electrode arms or the distal portion of the electrode lead immediately adjacent to those arms. The metal spacing sleeve is slidable along the telescope stem as the electrode assembly is advanced and retracted and, because of the direct contact between the spacing sleeve and the telescope stem, it has been necessary in the part to insure adequate insulation between the electrode and the sleeve.
To date, all new and alternative surgical therapies have generally failed to exhibit similar efficacy and durability, however, they have shown certain advantages in minimizing morbidity, the mount of blood loss that is experienced and are easier to perform. There is a need for a safer and less morbid approach than TURP that exhibits similar durable efficacy.
The second group of surgical therapies require local anesthesia without the need for general or spinal anesthesia. These treatments utilize different energies to deliver thermal therapy to the prostate. They include transurethral microwave thermotherapy (TUMT), transurethral thermal-ablation therapy (T#), high intensity focused ultrasound (HIFU), laser delivered interstitial thermal therapy (LDIT), and transurethral needle ablation of the prostate (TUNA). These treatments are less morbid that conventional TURP. Such thermal therapies are currently under investigation and will require completion of phase three trials and FDA approval before they make their debut into the market.
There is a need for a bloodless TURP apparatus, as shown in FIG. 1, thus alleviating virtually all of the problems of the standard TURP devices. This can be achieved in a TURP apparatus which provides simultaneous cutting and coagulation.